Greetings everyone,
Can anyone hep me out with the following problem which I have never had occur before and am bashing my head against the wall trying to resolve it.
The boat is my take on an MMM Norton cross with the following spec- twin screw,70mm Kort nozzles, Kort eze prop shafts, 70mm Propshop 4 blade Kort props, twin T12 motors with U/J type couplings.
Now the problem- everything is now in place shafts are parallel and square to the centre line, Kort nozzles are plumb and square to centre line, motors at the correct angle and straight (motors were run to check alignment prior to final fixing in place). However when I run the motors clockwise no problem whatsoever but when I run them anti clockwise in a few seconds the shaft screws tight and would completely lock up if left running.
The detail of assembly from the prop through to the motor is thus- propeller,brass locknut, brass washer, into the Korteze shaft, inside the hull brass washer,locknut (end float in shaft), locknut tightened onto the splined brass insert of the coupling, plastic centre of the U/J type coupling, splined brass insert onto the drive shaft of the motor.
I have checked and double/treble checked the clearance and tightness of everything, I have removed the motors to check the spin off the shafts for binding (all fine), had the motors running forwards and backwards in the vice (no problems and smooth), I've swapped the two shafts over (still the same), I tried a second locknut in front of the first brass nut at the shaft end locking the insert to this and it still jams.
I tried a completely different motor and it still jammed going anti clockwise, I've changed the coupling to the MMM rubber type it still jams. I can't seem to figure out how this can happen with the insert and brass nut locking themselves even if the inside of the hull end is right at the end of the thread with freeplay. Its driving me mad!
Help please? all advice greatly appreciated, what I do not understand is that I have built all of my boats prior to this exactly the same way but never had this problem.
Thanks in advance.
Regards,
Faz.